John Singer Sargent (1856-1925) painted in watercolors for the first time when he was 12 or 13. He used the medium for its own sake, but also as a kind of visual notation, recording aspects of the lands — chiefly Italy and Switzerland — through which he traveled with his family as an unusually peripatetic youth.

He was learning how to look, how to render what he saw, and how to get a feel for the hinge connecting those two functions — that hinge we refer to as an artist’s style, or vision.

Sargent’s footloose ways persisted into adulthood, as he carved out a reputation as the preeminent society portraitist of his generation — the painter of, among others, two of Boston’s best-loved works of art: “The Daughters of Edward Darley Boit” in the Museum of Fine Arts, and “El Jaleo,” in the Isabella Stewart Gardner Museum (both painted in oils in 1882).

Sargent continued to use watercolors intermittently, and with great brio, over the next three decades. His style adapted to various influences, including the urban realism of Auguste Manet and early James Whistler, and later the Impressionism of Camille Pissarro and Claude Monet.

But his manner of painting was responsive above all to the joys of looking. Not just any kind of looking but, increasingly, to a certain kind of fleet looking we instantly recognize as modern: the brief but relishing glance of the curious and comfortable traveler.

John Singer Sargent Watercolors

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In 1890, Sargent received a commission to paint a scheme of large religious murals for the Boston Public Library. For the next decade, the commission, complemented by Sargent’s thriving line in portraiture, pushed his landscape painting to the side.

But it was precisely that BPL commission, which would sustain him until the end of his life, that brought about a major change in his work in about 1902. By this time, Sargent, in his mid-40s, had finally acquired a house of his own in London. He had completed the first phase of the BPL mural cycle. And he was sick of painting society portraits.

Financially secure (thanks in part to the mural commission), he returned to watercolor and to landscape with renewed vigor and ambition, and a new sense of freedom. The watercolors he produced over the next decade — the first tranche of which was purchased en masse by the Brooklyn Museum, and the second tranche of which was acquired by the Museum of Fine Arts — are the subject of a ravishing show, which opens on Sunday at the MFA after enjoying a summer run in Brooklyn.

The exhibition is large: It has 92 watercolors spread across about a dozen galleries, each one sprinkled with related oil paintings. It is also beautifully installed and intensely satisfying. Long overdue, it marks the first time these two bodies of work, each one treasured by its institutional owner, have been united and displayed together.

The curators, Erica Hirshler from the MFA and Teresa Carbone from the Brooklyn Museum, have organized the works by theme rather than by date or by place. Their motive — to focus attention on the works rather than the artist’s biography — is sound. Mapping Sargent’s movements in any given month is in any case like trying to trace the trajectory of a firefly.

Sargent’s eye for the external world had a quality that combined slow-burning ardor with insatiability. And perhaps also a cooler sense of being challenged: He knew he was preternaturally gifted. Each view, however majestic, or however odd-angled and humdrum, must have triggered a kind of test: Can you rise to this, too?

He could. Sargent’s eye for Venice was especially ardent — he called it “a sort of fountain of youth.” He returned to it regularly, both before and after 1900, and produced more watercolors (nearly 150) there than anywhere else.

The show’s first gallery is devoted to Venetian views, many of them painted from the water, and all favoring pungent and partial views — “slipping glimpses” as Willem de Kooning might have called them — over sweeping vistas. We see, here and throughout the exhibition, how Sargent used underdrawing in light pencil to give definition to impressions that might otherwise have been too amorphous. His handling of white — both the untouched white of the paper and the superimposed touches of opaque white, often combined with a wax resist to give texture, and sometimes built up into a thick impasto — is particularly dazzling.

Sargent’s BPL commission triggered an interest in biblical sites and in the contemporary culture of the Middle East, an interest shared by many at the time, and shaped by the (mostly erroneous) assumption that the contemporary inhabitants of these lands lived comparably to their biblical ancestors.

Sargent met every technical challenge he could contrive with a confidence that can startle. The performance itself is riveting.

Studies of Bedouin Arabs and gypsies in these lands dominate the second gallery. They include some of Sargent’s most captivating work. Extraordinarily intense blues set off two piercing stares in “Bedouins,” while in “Bedouin Mother,” which shows a standing mother holding her child, conventional expectations of portraiture are reversed. The subjects’ faces are almost entirely lost in a tent’s shadow, while brilliant sunlight bounces off their limbs and hands.

Sargent devoted approximately three months a year (August to October) to painting expeditions on the European continent. He painted in oils alongside his watercolors. But there was no sense of the lighter, brisker medium being subordinate to the other. On the contrary, the ambition behind the watercolors is palpable from the outset.

A small gallery is given over to images of Sargent’s companions lounging around during these late summer months, often by mountain streams in the Alps. Here, Sargent manipulates figures that appear casually posed to suit his purposes, taking up the spirit of seaside pictures by Manet and Degas. (Degas: “The air you breathe in a painting is not necessarily the same as the air out of doors.”)

In “Dolce Far Niente,” for instance (the beautiful Italian phrase denotes “pleasant idleness”), his manservant, Nicola d’Inverno, poses for all three male figures. In the gorgeous “Zuleika” (an Arab name meaning brilliant and lovely), Sargent dresses his female companion in a dress he had brought back from the Holy Land. The playfulness of the conceit — Orientalism almost as a joke — anticipates Matisse and his odalisques in Nice.

“Simplon Pass: Reading,” from about 1911, is one of a number of works featuring Sargent’s beloved niece Rose-Marie. (He described her as “the most charming girl who ever lived.” When she died in Paris in 1918 — the Germans bombed the church she was in — Sargent was devastated.)

However, even Rose-Marie is treated as a kind of cipher for Sargent’s pictorial preoccupations. Lovely as it is, her face plays second fiddle to a turquoise umbrella and her companion’s voluminous white dress, which reflects subtly colored shadows.

In case, for some reason, you doubted Sargent’s ability to paint a portrait in watercolor, another small gallery includes a dazzling array of probing portraits, each one imbued with specificity and sympathy. None is better than “A Tramp.”

The run of galleries continues, each one more limpid, more beautiful, it can seem, than the last, and each theme — boats tied up in harbors, the marble quarries at Carrara, Italian villa gardens, “Sunlight on Stone” — providing ample pretexts for virtuosic display.

Richard Ormond/Museum of Fine Arts, Boston.

A photograph of Sargent (1856-1925) at work outdoors.

Sargent met every technical challenge he could contrive with a confidence that can startle. The performance itself is riveting. But he did so precisely at a time when the modernist avant-garde, surging suddenly to life, was discarding virtuosity as a fundamental value of art.

Artists like Matisse and Picasso, following in the footsteps of Cezanne, van Gogh, and Gauguin, were embracing awkwardness and an ideal of childlike simplicity. Kicking against what they perceived to be a glut of virtuosity — a virtuosity severed from deeper feelings; a virtuosity that had simmered too long in the sickly syrup of a clapped-out civilization — they were producing works of shocking gaucheness.

Sargent’s reputation was bound to suffer when the modernists won over their public, as eventually they did.

These watercolors, as Erica Hirshler discovered in her researches, were never intended for sale. It was only Sargent’s friend, Edward Darley Boit (the father of the famous daughters), who pushed for them to be sold to Brooklyn and Boston.

Sargent’s decade of gilded autonomy, which produced such a gush of freedom and high spirits, did not, alas, do much to enhance his reputation. As the new century advanced, no one seemed completely convinced that Sargent belonged to it.

Whether or not his reputation deserved to suffer in this way is immaterial. What matters is whether we can find urgent uses for Sargent’s virtuosity today.

One such use — sheer beauty, and the ideal of fluency and grace it stands for — has always adhered to these works, and always will. On most days, it is more than enough.

The underlying difficulty is that, simply put, we are troubled today, and we tend to trace the onset of so many of our troubles back to Sargent’s time: the Edwardian age, the onset of modernity, the eve of global catastrophe. We look back and, with touching naivete, expect the great artists of that period to reflect, or at least hint at, those oncoming troubles.

We are met, instead, with Sargent, who was, at least on the evidence of his pictures, the most untroubled artist of his time.

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